Measles virus-specific IgM antibodies and IgM-class rheumatoid factor in serum and cerebrospinal fluid of subacute sclerosing panencephalitis patients

La panencéphalite sclérosante subaiguë de la rougeole

La panencéphalite sclérosante subaiguë (PESS), une complication tardive de la rougeole, est encore présente lors d’épidémies de cette maladie dues aux insuffisances de la vaccination. Après un rappel historique, nous aborderons la physiopathologie de la PESS et l’importance des critères diagnostiques. De nombreux travaux portant sur les paramètres de l’immunité innée et sur ceux des réponses interféron tendent à montrer une baisse de l’activité de l’immunité cellulaire au cours de cette maladie. Nous formulons ici plusieurs hypothèses s’appuyant sur des publications concernant différentes formes de la maladie : congénitales, périnatales, formes à incubation courte, semblables à l’encéphalite aiguë à inclusions (EAI), formes d’évolution rapide, formes retrouvées chez les immunodéprimés ou chez l’adulte. Des formes familiales ont également été identifiées, suggérant une origine génétique. Selon la durée de la période de latence entre rougeole et la PESS, deux groupes de patients ont été individualisés, incitant à des analyses rétrospective et prospective des exomes de ces malades. La connaissance des gènes participant à la maladie devrait être utile pour la compréhension de la physiopathologie de la PESS mais aussi d’autres infections neurologiques tardives dues à des virus à ARN.

Measles Sclerosing Subacute PanEncephalitis (SSPE), an intriguing and ever-present disease: Data, assumptions and new perspectives

BACKGROUND

Subacute sclerosing panencephalitis (SSPE) is a rare, non-treatable and fatal neurological complication of measles, still present due to the return of the epidemic linked to the loosening of vaccination policies. Its mechanism remains unexplained.

OBJECTIVE

The main objective was to investigate explanatory variables relating to the risk of developing SSPE and its pathophysiology.

METHODS

Literature analysis was focused on different varieties of SSPE: perinatal forms, short-incubation forms similar to acute measles inclusion body encephalitis (MIBE), rapidly evolving forms, forms occurring in the immunosuppressed, adult forms, and family forms. In addition, several studies on the parameters of innate immunity and interferon responses of patients were analyzed.

RESULTS

Two main data were highlighted: a relationship between the so-called fulminant forms and the prescription of corticosteroids was established. In familial SSPE, two groups were individualized according to the duration of the latency period, prompting an analysis of patient exomes.

CONCLUSION

Treatment with corticosteroids should be banned. Knowledge of the genes involved and epigenetics should be useful for understanding the pathophysiology of SSPE and other late-onset neurological infections with RNA viruses.

Rheumatoid factors: host resistance or autoimmunity?

Rheumatoid factors (RFs), autoantibodies that bind to the Fc portion of IgG, are important in the immune response. RF-committed B-cells exist in the circulating lymphocyte pool in a high frequency (approximately 1-2 %) in normal individuals and in patients with pathological conditions associated with the sustained levels of circulating RF, such as rheumatoid arthritis (RA), Sjogren's syndrome (SS), and mixed cryoglobulinemia, associated with hepatitis C virus infection. RFs are induced by many infectious entities (viruses, bacteria, parasites) as a consequence of a secondary immune response to the pathogen, but usually the response is transient. It is likely that RFs play an important role in the host's defense against infection, both at the cellular level, where the RF B-cell can be an antigen presenting cell which can promote the antipathogen response, and at the humoral level, where RFs can contribute to the mopping up of the IgG antipathogen antibodies by contributing to immune complex formation and clearance. There has been much research on RFs in chronic pathological conditions, and the literature pertaining to their origin, structure, binding specificities, and possible roles in disease are discussed. The importance of the host defense, sometimes at the expense of an autoimmune response, is a balance that needs to be considered in light of a possible outcome of health or disease.

Low mumps antibody levels induced by mumps-measles-rubella vaccinations in type 1 diabetic children

Mumps-measles-rubella vaccination-induced antibody responses were studied in Type 1 diabetic children to find out the possible aberrations in mumps antibody responsiveness previously seen after natural mumps in Type 1 diabetic children. Mumps, measles, and rubella virus antibodies were studied in 364 newly diagnosed Type 1 diabetic subjects, their 240 non-diabetic siblings and 59 age- and sex-matched, unrelated, non-diabetic control subjects who all had received mumps-measles-rubella vaccine but had not had the respective infections. Sera were collected from all children at the time of the diagnosis of diabetes in the index case which was on average 2.5 years after the mumps-measles-rubella vaccination. The levels of IgG class mumps virus antibodies were lower in diabetic patients than in their non-diabetic siblings (p < 0.0005). This difference was most pronounced in males as male patients had significantly lower IgG mumps antibody levels than female patients. Rubella and measles IgG antibodies did not differ between patients and control subjects. The results are in accordance with previous studies suggesting a selective decrease in mumps antibody levels in Type 1 diabetic children. As the exposure to mumps virus had been exactly the same in all study groups, low mumps antibodies in diabetic children suggest decreased responsiveness rather than different number of past infections in these patients.

Fluctuation of virus antibody levels in healthy adults

In order to determine fluctuations in virus antibody levels, blood specimens were collected weekly from 13 healthy adults during a nine-week period and tested by enzyme immunoassay for IgG antibodies against measles, rubella and cytomegalovirus. In 29 of 35 subject-titer pairs the difference between the highest and lowest titers observed was less than twofold, in five cases it was between twofold and threefold, and in one case it was 3.3-fold. These differences were higher than those caused by intraassay variation alone. The results indicate that some physiological fluctuations seem to occur in the antibody levels of healthy individuals. Although the fluctuations are usually small, care should be taken if titer increases less than fourfold are used as a criterion to indicate recent infection.

Measles IgM antibodies in cerebrospinal fluid and serum in subacute sclerosing panencephalitis

Using a direct enzyme-linked immunosorbent assay (ELISA), we examined serum and cerebrospinal fluid (CSF) from six patients with subacute sclerosing panencephalitis (SSPE) and control subjects for presence of measles-virus-specific IgM antibodies. All samples from the SSPE patients contained demonstrable titers of measles antibodies. The levels of measles IgM antibodies were higher in CSF diluted 1:5 than in serum diluted 1:50, reflecting a local production of IgM antibodies in the central nervous system. Antibody titers remained constant over the course of SSPE in three of the patients followed for three to six months. The IgM ELISA had high sensitivity as well as specificity and was not complicated by false-positive reactions owing to the presence of rheumatoid factor.

Synthesis of measles virus-specific IgM antibodies and IgM-class rheumatoid factor in relation to clinical onset of subacute sclerosing panencephalitis

Thirty-seven serum and 37 cerebrospinal fluid (CSF) specimens from 27 patients with subacute sclerosing panencephalitis (SSPE) were tested for measles virus (MV) IgM antibodies and IgM-class rheumatoid factor (RF) to determine if a temporal relationship exists between SSPE onset and these immunoglobulins. Sensitive solid-phase radioimmunoassays were used for immunoglobulin detection. Five of six MV IgM-positive CSF, both MV IgM-positive sera and six out of eight sera with elevated RF levels were collected within 1 yr of SSPE onset. Also collected during this time were six other sera having high binding in the MV IgM assay, which was not due to MV-specific IgM antibodies. Two of these sera had as high or higher binding of IgM to a Vero cell control antigen, suggesting involvement of an IgM-class autoantibody. The other four sera had false-positive MV IgM assay results due to RF interference. RF interference was dependent on both the titer and avidity of the MV IgG antibodies involved. Three conclusions can be drawn from these results. First, MV IgM antibodies and elevated RF levels are not markers for acute SSPE, despite the tendency for their synthesis at this stage of the disease. Second, immunoassay analysis of viral IgM antibodies must employ an appropriate control antigen to account for background IgM binding. Finally, even if RF levels are normal or near normal, a false-positive IgM immunoassay result can still occur if antigen-specific IgG antibodies in the same sample have the right combination of titer and avidity.

Coincidental fluctuations of humoral immunity and clinical progression in a patient with subacute sclerosing panencephalitis

Serum and cerebrospinal fluid were obtained from a 6-year-old male with subacute sclerosing panencephalitis (SSPE). Specimens were collected over a 9-month period beginning in the unusually acute phase and ending in a more quiescent phase of the disease. Immune complexes, auto-antibodies and viral antibodies were measured by radio-immunoassays. Fluctuations in these humoral immune parameters coincided with cessation of the acute phase of this disease. The results show that neurological changes in SSPE patients can be reflected in immune responses within both the peripheral circulation and the central nervous system.

Demonstration of a transient rheumatoid factor in the acute phase of hepatitis non A, non B

The evaluation of an enzyme-linked immunosorbent assay (ELISA) test designed to detect antigens of hepatitis non A, non B (HNANB) revealed that a rheumatoid factor (RF)-like reaction was interfering. This RF-like reaction was not detectable by routine screening methods for RF, such as latex agglutination or the Waaler Rose test. Testing of sequential sera of chimpanzees with acute HNANB showed that this RF-like reaction was present in the acute phase of HNANB simultaneously with alanine aminotransferase (ALT) elevations. Characterization of this RF-like reaction revealed the presence of an IgM antibody against human IgG that banded in CsCl at 1.3 g/ml and at 19S in sucrose gradients. Absorption with IgG-coated latex particles and anti-human IgM gave further evidence of an RF. By testing sera of patients with different forms of acute viral hepatitis, it was demonstrated that an RF-like factor was also present in seven sera from 9 patients with acute hepatitis A, in two sera from 11 patients with hepatitis B, and seven sera from 11 patients with acute HNANB. The rise of RF in the acute phase of hepatitis A may be an effect of polyclonal stimulation of IgM producing B lymphocytes. The high prevalence of RF in HNANB remains unclear as no polyclonal stimulation of IgM has been observed.

Mitogen and antigen stimulation of multiple sclerosis cerebrospinal fluid lymphocytes in vitro

Responses of cerebrospinal fluid (CSF) and peripheral blood (PB) lymphocytes from 20 MS patients to phytohemagglutinin (PHA), measles, rubella, mumps and herpes simplex virus antigens were followed during periods of from 6 to 13 months. Up to 6 examinations, each with 1-5 stimulants, were performed with a lymphocyte blast transformation test. Most of the patients responded with their CSF cells to PHA (14/19) and at least to some of the viral antigens tested (15/20) during the follow-up. Although the maximal responses of CSF and PB cells to PHA and measles virus antigen were of the same magnitude, non-reactive or weakly responding lymphocytes were more common in CSF than in PB. In 7 of 15 patients having viral antigen responsive CSF cells simultaneous reactivity to several antigens could be shown. The stimulation results of CSF lymphocytes did not correlate with the numbers of CSF leukocytes or the intrathecal IgG synthesis. A negative correlation was observed between the strength of the CSF cellular response to PHA or measles virus antigen and the rate of intrathecal antibody synthesis to measles virus antigen, suggesting that the stimulated cells may at least partially represent suppressor cells.

Intrathecal synthesis of virus antibodies in multiple sclerosis patients

A follow-up study on the intrathecal synthesis of viral antibodies in multiple sclerosis patients was made on 28 patients over a period of about 2 years. Serial serum and cerebrospinal fluid specimens were assayed for antibodies against measles, rubella, parainfluenza type 2, respiratory syncytial, mumps, influenza A, influenza B, adeno, and herpes simplex viruses by employing a solid-phase enzyme immunoassay technique. All patients had local antibody synthesis against one or more of the antigens studied. Rubella and measles virus antibodies were found with the highest frequency and were synthesized at the highest rate. Simultaneous intrathecal antibody synthesis against the greater number of the viruses studied was associated with higher local immunoglobulin G synthesis. A good overall correspondence in the fluctuations of the different viral antibodies synthesized intrathecally was usually found. Sometimes the changes in intrathecal antibody levels correlated well with the changes in immunoglobulin G index and sometimes not. These fluctuations could not be correlated with the clinical course of the disease. The results of this study suggest that the viral antibodies studied are not relevant to the etiology or the pathogenesis of multiple sclerosis.

IgM-class rheumatoid factor in serum and cerebrospinal fluid of multiple sclerosis and matched neurological control patients

Paired serum and cerebrospinal fluid (CSF) specimens from 30 multiple sclerosis (MS) patients and 30 matched neurological control (NC) patients were quantitatively tested for IgM-class rheumatoid factor (RF). Significantly elevated RF levels were found in serum from 6 MS patients and 12 NC patients. Seven of the latter 12 patients had a diagnosis of recurrent head pain. RF was detected in CSF from 2 MS patients and 2 NC patients. In 3 of the 4 cases, this could be explained by blood-brain barrier damage or normal diffusion of RF into CSF. Intrathecal RF synthesis was found in the remaining MS patient. These results suggest that RF production may be related to underlying pathological mechanisms in at least some MS and NC patients. They also confirm that RF must be carefully accounted for in etiological studies designed to demonstrate pathogen-specific IgM antibodies in, for example, MS patients.